In the 1950s and 60s, research by Roger Sperry and Joseph Bogen, seemed to show conclusively that the human brain was not just shaped into two halves physically, but also that each half has a different way of seeing the world, a different way of processing sensory inputs. Experiments on patients whose corpus callosum – the main linkage between the two brain halves – had been severed showed that not only did each side share the processing, but that each side had different capabilities. Patients who had no right or no left hemisphere after illness or an accident also showed up as different. The right side of the brain seemed to be about context, appreciation of wholes, beauty and harmony and, most interestingly, new experience[1]. The left side seemed to prefer logic, symbols, parts rather than wholes, scatology rather than beauty, routines, processing. While the right brain seems to intuit quite naturally a sense of wonder at the very existence of the world, the left brain seeks to explain where that world came from.

Now this was actually not a new idea: the ancient Greeks inferred from the bicameral nature of the physical brain that human beings had two natures – one logical and nit-picking, and one intuitive and holistic. So the philosophical – metaphorical, if you like – concept of a brain that could function in two ways (indeed had to function in two ways) was born many centuries ago.

Throughout the ages this was referred to regularly. It may have helped inform the philosophy of Kant, where our logical side deals with ‘phenomena’, and yet also we are intuitively aware of things in themselves – ‘noumena’. (Though Kant was anxious to show that logically we could never know anything directly.)

So the metaphor of the two ways of the mind was well established. But the evolution of neuroscience in the 20th century – which proceeded from seeing the brain as a giant clockwork mechanism to a kind of electro-chemical computer – meant there was no longer a theoretical basis for this right-left divide. In fact the new metaphor of the brain as super computer – energised by the growth and dependence on computing as big business – was so dominant that the brain became, for a while, all that was essential about being human. It is little surprise that ‘the brain in a vat’ became a common idea at the time, which partly materialised as the fad for freezing heads in the vain hope that centuries later science would have advanced to a point where the dead brain could be revived and plugged into a robot body. The idea – common in ancient psychology – of the brain having different ‘centres’ in the body was laughed at (though we’ll see that recently the tune has changed). The model of a single centralised processing unit was firmly established and spread as the dominant mind metaphor of our time.

But because it was a limiting idea, people naturally rebelled against it. Suggesting, as some technophiles did (including in his earlier days, Nobel Laureate Richard Feynman) that all poetic, artistic and spiritual impulses were just a refined kind of nonsense goes against the entire history of the human race. For a while, however, technology seemed to deliver such amazing progress that it was possible to forget this.

For a while… But digesting the experiences of WWI, WWII, and the atomic bomb caused a reaction against scientific and technological utopian thinking which was well established by the time the right-left brain research came out. Here seemed to be real hard evidence ‘from the enemy’, so to speak, that meditation, intuition, creativity and foresight were all very real and occupying real estate alongside duller neurons assigned to perception, logical reasoning, and autonomic body systems.

And then things got really wild.

Apart from the more reasoned books by Robert Ornstein and others, there was a flood of publications linking left and especially right brain function to everything from investment strategies to cooking. Which in a way wasn’t incorrect since both sides of the brain are involved in pretty much everything. However the panacea thinking was increasingly evident, and scientific research, proceeding as it does in cyclical fashions of acceptance and rejection, started to find a lot of evidence that the brain was in fact a unitary organ, that exclusive left and right functions were hard to find and even harder to assign conclusively to intuitive or logical activities.

Part of the problem was, of course, that the left-brain bias of scientific research makes conceptualising right-brain activities difficult a priori. The right brain can conceptualise the left brain easily. But if you accept primacy of language, logic, and reasoning from evidence, then where do you put intuition? Where do you put an instant holistic insight into something?

The moment you start to take apart such experiences using the dry language of logic it shrivels up and disappears. Rather as the butterfly, once dismembered, ceases to be a butterfly, simply a catalogue of parts. And coming across such a collection one could be forgiven for accepting them as mere parts, rather than assuming that they are all part of something bigger and more beautiful.

Unless of course you had already seen a butterfly, or heard others speak of them. Or intuited that they exist…

But all through the promotion of, and then reaction to, the right/left brain hemisphere division, research quietly continued. By the beginning of the 21st century the tide was beginning to turn a little. The publication of Iain McGilchrist’s The Master and his Emissary[2] saw a summation of the latest evidence and the most eloquent defence yet of the right/left division of the brain.

But just as importantly, McGilchrist made his case bomb-proof against further neuroscientific research. He adroitly showed that even if the division has no physical basis, the metaphor is so useful we’d be fools not to use it. We think in metaphors; it is how we understand the world. Indeed analogies and metaphors are two of the things the left brain – and computers – find very hard to use. Hence the difficulty even now of computers recognising distorted fonts, since to comprehend them you need analogous thinking – which could be defined as ‘thinking that happens all at once’.

Thankfully, research in the last few years has done everything to substantiate McGilchrist’s position. We now know that intelligence is distributed throughout the body. The abdomen is a centre of emotion, as ancient psychology suggests. The brain/body continuum is finally a mainstream concept. Right/left hemisphere specialisation looks rather tame alongside a ‘thinking’ spine and stomach.

We know now from stroke-recovery research that the brain is not a computer which starts to fall apart around the age of twenty.[3] It is in fact a learning organ which stays healthy, throughout life and into old age, with constant learning challenges. Once we understand the that primary function of the brain is to learn and keep learning, the idea that it is a form of logical calculating machine (like an electronic computer) alone has less traction. Learning requires goals, motivation, a sense of meaning. A reductionist left-brain view cannot accommodate these things. You can’t construct a passion or an interest logically; and to call it ‘random’ is to abuse the language. If some of the most important creations of man are ‘random’ then the word ceases to have any meaning.

The Master and his Emissary is rather heavy going at first; luckily, though, the gist can be gathered from the last two chapters (with a bit of flipping back to catch missed references). The main concern which the book addresses is the left-brain emphasis in society, which has been accelerating for various reasons since the Enlightenment. Evidence of this is all around us: lengthy and verbose laws that are so complex and long that no single person ever reads them in their entirety, let alone the politicians who vote on them; the requirement to ‘critique’ and verbalise about subjects – art, drama, dance – that are there to be experienced, not talked about; the growth in mental disorders associated with excessive left-brain dominance.

One of the most useful insights that McGilchrist provides in this regard is his assertion – backed by the evidence of other researchers[4] – that schizoid states can be seen as left-brain dominance. Evidence shows that when the right brain is damaged we see symptoms that mimic schizophrenia.

The right-left dichotomy also provides useful insights into creativity. Instead of viewing ‘all creativity as good and akin to something a bit spiritual’, we see that there are two kinds. Of course there is, as with all human endeavour, a mix of the two sides – but left rather than right dominance produces a different sort of creativity. Left brain creativity is rather like the cut-up technique of William Burroughs and Brion Gysin – recombining in a novel way what is already known. It is the kind of creativity you see at work in Hollywood – after all, why not mix Alien with Predator and get… Alien versus Predator? Left-brain creativity can be taught or at least encouraged through mixing-and-matching, whereas right-brain creativity comes from somewhere else. Right-brain creativity is the result of being in a certain state of mind – what might be called inspiration, though that has tended to become a worn-out term over time. By entering into the right state of mind, what we thought we knew is revealed more truthfully for the first time. The ‘right state of mind’ is nothing grand and romantic, rather it is experienced as a kind of dropping down a gear, a lessening of ‘trying too hard’, adopting instead a more honest, intuitive approach to something – be it engineering or sculpture or poetry. Often a new metaphor or conceptual leap is made. Owing to the left-brain dominance of our current society, such leaps are thought excessively rare and are called ‘genius’. But perhaps they are more commonly available than we think.

[1] Goldberg and Costa 1981

[2] Iain McGilchrist The Master and his Emissary 2009

[3] Dr Michael Merzenich Softwired 2013

[4] L.A.Sass Madness and Modernism 1992